Investigate crash on `dotnet restore` in Microsoft-internal repo

[rainersigwald]

Report of a crash using .NET SDK 10.0.100-rc.2:

> dotnet restore
D:\CxCache\.A\DotNetSDK.RGUCrN4KjzB55QtGl8GCWA\sdk\10.0.100-rc.2.25502.107\NuGet.RestoreEx.targets(19,5): error
  '{' is an unexpected token. The expected token is '"' or '''. Line 2, position 33.
     at System.Xml.XmlTextReaderImpl.Throw(Exception e)
     at System.Xml.XmlTextReaderImpl.Throw(String res, String[] args)
     at System.Xml.XmlTextReaderImpl.ParseAttributes()
     at System.Xml.XmlTextReaderImpl.ParseElement()
     at System.Xml.XmlTextReaderImpl.ParseElementContent()
     at System.Xml.XmlLoader.LoadNode(Boolean skipOverWhitespace)
     at System.Xml.XmlLoader.LoadDocSequence(XmlDocument parentDoc)
     at System.Xml.XmlDocument.Load(XmlReader reader)
     at Microsoft.Build.Shared.SolutionConfiguration.GetProjectConfigurations(String xmlString)
     at Microsoft.Build.Shared.SolutionConfiguration..ctor(String xmlString)
     at Microsoft.Build.Graph.ProjectInterpretation.GetReferences(ProjectGraphNode projectGraphNode, ProjectCollection projectCollection, ProjectInstanceFactoryFunc projec
  tInstanceFactory)+MoveNext()
     at Microsoft.Build.Graph.GraphBuilder.ParseReferences(ProjectGraphNode parsedProject)
     at Microsoft.Build.Graph.GraphBuilder.ParseProject(ConfigurationMetadata configurationMetadata)
     at System.Lazy`1.ViaFactory(LazyThreadSafetyMode mode)
     at System.Lazy`1.ExecutionAndPublication(LazyHelper executionAndPublication, Boolean useDefaultConstructor)
     at System.Lazy`1.CreateValue()
     at System.Lazy`1.get_Value()
     at Microsoft.Build.Graph.ParallelWorkSet`2.ExecuteWorkItem()

[rainersigwald]

@ericstj pointed out offline that if the second line of the XML was

  <ProjectConfiguration Project={

then there'd be an unexpected { on character 33, and that almost makes sense since it's written here:

msbuild/src/Build/Construction/Solution/SolutionProjectGenerator.cs

Lines 268 to 276 in 4cd2425

	xw.WriteStartElement("SolutionConfiguration");
	// add a project configuration entry for each project in the solution
	foreach (ProjectInSolution project in solutionFile.ProjectsInOrder)
	{
	if (project.ProjectConfigurations.TryGetValue(solutionConfiguration.FullName, out ProjectConfigurationInSolution projectConfiguration))
	{
	xw.WriteStartElement("ProjectConfiguration");
	xw.WriteAttributeString("Project", project.ProjectGuid);

But why would that WriteAttributeString decide not to quote the attribute?

[ericstj]

I was thinking that maybe something in the process of reading/writing properties and passing around something ran afoul of escaping logic. IOW - XML wrote the quotes, but they got stripped out later. Lots of places that MSBuild tries to understand strings and strip out quotes, including places that changed between .NET 8 and 10 - so this feels like the most likely cause.

I couldn't reproduce myself by trying just a simple sln, even copy pasting the content that the internal team shared from their SLN, so there must be something unique to their environment / paths / etc. Maybe some sort of unique thing in a path, like a semi-colons and equals signs in a directory names or something evil like that.